My ~/.gitconfig (with sensitive portions removed)

.gitconfig

[color]
	ui = auto
[core]
	autocrlf = input
	excludesfile = /Users/atcodes/.gitignore_global
[push]
	default = tracking
[alias]
	lg = log --graph --pretty=format:'%Cred%h%Creset -%C(yellow)%d%Creset %s %Cgreen(%cr,%an)%Creset' --abbrev-commit --date=relative
	st = status -sb
	ignored = ls-files --others -i --exclude-standard
	unstage = reset HEAD
	df = diff --color-words
	yolo = !git add -A . && git commit -m "YOLO" && git push origin master
[difftool "sourcetree"]
	cmd = opendiff \"$LOCAL\" \"$REMOTE\"
	path =
[mergetool "sourcetree"]
	cmd = /Applications/SourceTree.app/Contents/Resources/opendiff-w.sh \"$LOCAL\" \"$REMOTE\" -ancestor \"$BASE\" -merge \"$MERGED\"
	trustExitCode = true

.gitignore_global

*~
.DS_Store